Direct positive photographs using color developers



Patented May 9, 1950 UNITED S TATES IDZFF'I CIE DIRECT POSITIVE PHOTOGRAPHS USING COLOR DEVELOPERS Dudley B. Glass and Forrest .A" Richey Rochestem' N. Y., assignci's to Eastmanliodak Company, Rochester, N. Y., a corporation of NewJersey- No Drawing. Application October 17, 1947; Serial No. 7 8057i "6 Claims.

.2 the silver halide grains' as described on pages 296 297 oizMees. f'llhefl'llhoory' of. the Photographic Process, '.19e2,.is esp c useful for the process otour invention.

Most, of. the.-.in enna1;.1ate im emulsi n are silver blDmDr' Qdid. nul ion of i h odide con ent. pr ierably Q nt inin at lea of iodide... Bottoms emulsion. is an emulsion.,0f this. 23 1 6 having a silver. iodide content of. ap-

piiO imatfilygflqp of the content of silver halide.

Qur inventignisnot,however, limited to the use of emulsions containingdsilver.iodide.

An, intet nalalatentimage? made as. described in. nevevandxnottapplio t o t i No- .intermediate or additional step other than treatn; 99,232.iiled neeember 61.1.1947, nowabandoned, ment' in the single developing solution which gives may alsobeugedfifigglldillgiO omginyention This aerial f he ser al f e ay be produced y emulsion is. prep.ared.-..by first forming in,the bubbling air through the developing solution in absence of. ammonia. andinoneor, mordstaEfis nta t the emulsion surfaoeof the phot silver salt. grains consisting least. partlyofa rap during deve p y Hiding en s 20 silver saltwhichiisdmoreisolublein..Water than Such asce n. pp S t y r nperoxide silver: bromide, subsequently. converting the grains to the developing 1 to silver. bromide oresilyer' bromoeiodideandifthe W have now und a a direct p s v silveriodide: content. of. the emulsionis. less than p a l h y be pmdllced Without the 8 0f 6% ca1culated-on the total silver halide-,treating a r al f ss e agents y vel p g the exp 25 such grains-Wuhan; iodinecompound to bring special emulsion in a developing solutioncontaint il r i di up: to ..-at .1east.v 6%,, ripening in a prim y aromatic amino d v pin agent preferably in-t-he:absence-of-:ammonimanduthen n an ve methylene coupler compound. either washing out some ofathe soluble .salts or he p t rap emulsion used in e process w-ashingout the wliole' of 'thesoluble. salts, folof our invention may be a suitable internallatent lowed. by t addition; f.. ]ub1e sa11-, 511011.35

ima mu su a a s v nb de. silver soluble chloride-or bromide. An example of an bromoiodide or silver chloroiodide emulsion. It emulsicn made i thi ayjs as follows;

should be undigested or, if digested; the digestion a 1 N shouldbe carried-out without the useof sulfur u Ion Inert gelatme 20 grams sens1t1z e1. A sultable emulsion 1S that known as 0 KC} 20 grams at C Burtons emulsion described H in -Wa1l, Photo- Wate'r 560 cc graphic Emulsions, 1929, pages 52 and 53.

Burtons emulsion is made as follows: Solution 21 1 A. Silver nitrate grams 100 40 @iig ggi zit-C.

Water "cubic centimeters 500 Ammonia-to form clear solution. sslution'Nov 3! 13. Potassium bromide "grams.-- 80 AgNOi C Potassium iodide do .50 Water 520 soft gelatin v---- 20 45 Solution NO. 4:

Water cubic centimeters 1000 KBr ;1 0

C. Dry gelatin grams- 250 K1 u l g B is heated to 70 0. andA, cold, added to B with W ater 500.00-

cpnstant ng, digested for 20 minutesat Run solutions Nos. ,2gand1-3 simultaneouslydnto 3., and al w to 0 w y s added a t r 50 soiutioniidi in-aivesselitak ng;9,0.se onds.to do being allowed to swell for 20 minutes in water, t i Then rip en-jorkminune at, 453 Next drained and melted. The emulsion is then set addsolution-lNol 4. Then-ripen for-20. minutes and washed. at 45 C. Next add:;235 ?ams:.0f inert zg lflt An internal latent image emulsion, thatqis, (dry).. Thfimripemat-Afi? C, for:- l5 minutesdur one'which forms the latent image mostlyinside ing which time the gelatine disso1ves;.- S et and.

3 shred the emulsion and then wash until free from all soluble bromide and then add about 150 cc. of solution of KCl (by weight), and then add water to make 3 litres.

An internal latent image type of silver halide emulsion may be defined as one which, when a test portion is exposed to a light intensity scale for a fixed time between /100 and 1 second, and developed for 4 minutes at 20 C. in the ordinary, surface developer (Example 1), exhibits a maximum density not greater than the maximum density obtained when the same emulsion is equally exposed and developed for 3 minutes at 20 C. in an internal type developer. Stated conversely, an internal latent image emulsion, when developed in an internal type developer (Example 2) exhibits a maximum density at least 5, and preferably at least 10, times the maximum density obtained when the same emulsion is exposed in the same way and developed in a surface developer (Example 1).

Our process depends on the use, with the internal latent image emulsion, of a developing solution containing an active methylene compound, a primary aromatic amino developing agent, little or no anti-foggant and no active silver halide solvent such as sodium thiosulfate or sodium thiocyanate. When these conditions are satisfied, immersion of the exposed emulsion in the developing solution yields a direct positive image at the same sensitometric speed as the negative speed of the emulsion.

The aromatic amino developing agent used in the developing solution may comprise any of the suitable aromatic amino developing agents normally used in color photographic processes such as the p-phenylenediamines and p-aminophenols. Derivatives of these developers formed by substitution in the amino group as well as in the ring such as the alkyl phenylene diamines and alkyl toluylene diamines may also be used. Suitable compounds as diethyl-p-phenylenediamine hydrochloride, monomethyl p phenylenediamine hydrochloride, dimethyl p phenylenediamine sulfate, 2-amino-5-ethylaminotoluene hydrochloride and the developing agents described in Weissberger U. S. Patent 2,193,015.

The active methylene compounds used in the developing solution are those which are normally used in color photography and contain a reactive methylene group of the following type:

Couplers of the phenolic hydroxyl type are not suitable for use according to our invention.

The following coupler compounds are suitable as the active methylene compound for incorporation in the developing solution: acetoacetanilide, 2,5 dichloro acetoacetanilide, omega benzoylacetanilide, omega-benzoyll-(p-tolyl sulfonamido)-acetanilide, Z-cyanoacetylcoumarone, 3- '(m-nitrobenzamido)-1-phenyl-5-pyrazolone and other compounds described in U. S. Patents 2,108,602, 2,271,238 and 2,369,489.

The developing solution should contain little or no anti-foggant. The use of certain antifoggants not containing labile sulfur such as benzotriazole may be tolerated but such compounds do not aid in obtaining the direct positlve action.

The developer should have a low sulfite content and should not contain any active silver halide solvent such as sodium thiosulfate or sodium thiocyanate. No silver halide solvent more powerful (as a silver halide solvent) than sulfite should be used.

An ordinary surface type developer, that is, one which develops an image only on the surface of the grains of an internal latent image emulsion is the following:

Example 1 Grams p-Hydroxyphenylglycine 10 Sodium carbonate (crystals) Water to 1 liter. Development time, 4 min. at 20 C.

An internal type developer, that is, one which develops an image inside the grains of an internal latent image emulsion, is the following:

Example 2 Grams Hydroquinone 15 Monomethyl-p-aminophenol sulfate 15 Sodium sulfite (anhydrous) 50 Potassium bromide 10 Sodium hydroxide 25 Sodium thiosulfate (crystals) 20 Water to 1 liter. Development time, 3 min. at 20 C.

Our invention will now be described by reference to the following specific example.

An emulsion such as that described in the Davey and Knott U. S. application Serial No. 790,232 described above was coated on a support, dried and exposed on an Eastman 2B Sensitometer (Journal Society Motion Picture Engineers, vol. 17, 1931, page 536). The exposed emulsion was then developed 15 minutes at 65 F. in the following developing solution:

Example 3 2-amino-5-diethyl-amino-toluene Grams hydrochloride 3 Sodium sulfite 5 Sodium carbonate 20 Sodium hydroxide 1 2,5-dlchloro-acetoacetanilide 3 Water to 1 liter.

Example 4 Z-amino-S-diethyl amino toluene Grams hydrochloride 3 Sodium sulfite (dessicated) 3 Sodium carbonate monohydrate 30 Sodium hydroxide 3 Acetoacet-2,5-dichloroanilide 3 When the exposed emulsion is immersed in this solution for only 30 seconds, no visible image is produced but a positive silver image is obtained when the emulsion is then immersed for 1 to 1 mi-nutes in a developer of the following compo- 'lhedeveloper of Example 5 is an active developer and by the use of the developers of Example 4 and Jilxample 5, an image is produced in 1 to 2 minutes as compared with a time of five or six minutes if thelilm is allowed to remain in the developer of Example 3 or Example 4 for the entire development time.

It .willlbe evident to those skilled in the art that our "process aifords a convenient means for obtain-inga direct positive photograph either in color or metallic silver by simple exposure and de- "velopment steps and avoids the necessity of high 'intensityexposures or a second exposure or redevelopment. It will be understood that the examples and modifications included herein are "illustrative only and that their invention is to be .t k n a limited only by the scope of the appended claims.

We claim:

1. The method of obtaining a direct positive :dye image in a silverhalide emulsion layer, which comprises exposing to light rays to which the emulsion is sensitive, a silver halide emulsion layer, a test portion of which upon exposure to a light intensity scale for a fixed time between /100 Land 1 second and development for 3 minutes at 20 C. in the following internal type developer Grams Hydroquinone Monomethyl-p-aminophenol sulfate -15 Anhydrous sodium sulfite 50 Potassium bromide 10 Sodium hydroxide ,25 Sodiumthiosulfate Water to 1 liter.

gives a maximum density at least 5 times the maximum density obtained when the equally exposed silver halide emulsion is developed for 4 minutes at 20 C. in the following surface developer (1):

Grams p-Hydroxyphenylglycine 10 Sodium carbonate 100 Water to 1 liter.

and immediately immersing said layer inasingle developing solution free of anti-foggant containing labile sulfur and free of silver halide solvent morepowerful as a silver halide solvent than sulfite and containing a primary aromatic amino developing agent and an active methylene coupler compound capable of coupling with the oxidation product of said developing agent to produce a dye image in said solution, for a length of time sufiicient to produce a positive dye image in said layer.

2. The method of obtaining a direct positive image in a silver halide emulsion layer, which comprises exposing to light rays to which the emulsion is sensitive, a silver halide emulsion layer, a test portion of which upon exposure to a light intensity scale for a fixed time between /100 and 1 second and development for 3 minutes at 5 20 C.- in. the following internal typ'e developer Grams *I-Iydroquinone l5 Monomethyl-p-aminophenol sulfate 1-'5 Anhydrous sodium sulfite 50 Potassium bromide --10 Sodium hydroxide 25 Sodium thiosulfate 20 Water-to '1 liter.

gives a maximum density at least 5 times the maximum density obtained when the equallyexposed silver halide emulsion is developed for 4 minutes :at 20 C. in the following surface developer (I):

Grams -p-Hydroxyphenylglycine 10 Sodium carbonate Water to 1 liter.

and then without intermediate treatment,-jrendering developable the silver halide grains in the unexposed regions of said layer by immersing said layer in a developing solution free .of antifoggant containing labile sulfur and free of silver halide solvent more powerful as a silver halide solvent than sulfite and containing a, primary aromatic amino developing agent and an active methylene coupler compound capable of coupling with the oxidation product of said developing agent to produce a dye image, and developing to metallic silver said grains thus rendered -developable.

3v The method of obtaining a direct positive image in a silver halide emulsion layer, which comprises exposing to light rays to which the emulsion is sensitive, a silver halide emulsion layer, a test portion ofwhich upon exposure to alight intensity scale for a fixed time between /100 and 1 second and development for 3 minutes at 20 C. in the following internal type developer Grams Hydroquione 1-5 Monomethyl-p-aminophenol sulfate 15 Anhydrous sodium sulfite 50 Potassium bromide '10 Sodium hydroxide 25 Sodiumthiosulfate 20 'Water to 1 liter.

gives a maximum density at least 5 times the maximum'density obtained when the equally exposed silver halide emulsion is developed for4 minutes at 20 C. in the following surface developer (I) Grams -p.-.Hydroxyphenylglycine 10 Sodium carbonate 100 Water to 1 liter.

and hen without intermediate treatment, rendering developable the silver halide grains in the unexposed regions of said layer by immersing said layer in a developing solution free of anti-foggant containing labile sulfur and free of silver halide solvent more powerful as a silver halide solvent than sulfite and containing a primary aromatic amino developing agent and an acetoacetanilide coupler compound capable of coupling with the oxidation product of said developing agent to produce a dye image, and developing to metallic silver said rains thus rendered developable.

4. The method of obtaining a direct positive image in a silver halide emulsion layer, which comprises exposing to light rays to which the emulsion is sensitive, a silver halide emulsion layer, a test portion of which upon exposure to a. light intensity scale for a fixed time between /100 and 1 second and development for 3 minutes at 20 C. in the following internal type developer Grams Hydroquinone 15 'Monomethyl-p-aminophenol sulfate 15 Anhydrous sodium sulfite 50 Potassium bromide 10 Sodium hydroxide 25 Sodium thiosulfate 20 Water to 1 liter.

gives a maximum density at least times the maximum density obtained when the equally exposed silver halide emulsion is developed for 4 minutes at 20 C. in the following surface developer (I):

Grams p-Hydroxyphenylglycine Sodium carbonate 100 Water to 1 liter.

and then without intermediate treatment, rendering developable the silver halide grains in the unexposed regions of said layer by immersing said layer in a developing solution free of anti-foggant containing labile sulfur and free of silver halide solvent more powerful as a silver halide solvent than sulfite and containing 2-amino-5-diethylamino toluene hydrochloride as the developing agent and an acetoacetanilide coupler compound capable of coupling with the oxidation product of said developing agent to produce a dye image, and developing to metallic silver said grains thus rendered developable.

5. The method of obtaining a direct positive image in a silver halide emulsion layer, which comprises exposing to light rays to which the emulsion is sensitive, a silver halide emulsion layer, a test portion of which upon exposure to a light intensity scale for a fixed time between /100 and 1 second and development for 3 minutes at C. in the following internal type developer Grams Hydroquinone 15 Monomethyl-p-aminophenol sulfate l5 Anhydrous sodium sulfite 50 Potassium bromide 10 Sodium hydroxide Sodium thiosulfate 20 Water to 1 liter.

gives a maximum density at least 5 times the maximum density obtained when the equally exposed silver halide emulsion is developed for 4 minutes at 20 C. in the following surface developer (I):

Grams p-I-Iydroxyphenylglycine 10 Sodium carbonate 100 Water to 1 liter.

and then without intermediate treatment, rendering developable the silver halide grains in the unexposed regions of said layer by immersing said layer in a developing solution free of antifoggant containing labile sulfur and free of silver halide solvent more powerful as a silver halide solvent than sulfite and containing 2-amino-5- diethylamino toluene hydrochloride as the developing agent and 2,5-dichloroacetoacetanilide, and developing to metallic silver said grains thus rendered developable.

6. The method of obtaining a direct positive image in a silver halide emulsion layer, which comprises exposing to light rays to which the emulsion is sensitive, a layer of silver halide emulsion in which at least 6% of the silver halide is silver iodide, a test portion of which upon exposure to a light intensity scale for a fixed time between and 1 second and development for 3 minutes at 20 C. in the following internal type developer (II):

Grams Hydroquinone 15 Monomethyl-p-aminophenol sulfate 15 Anhydrous sodium sulfite 50 Potassium bromide 10 Sodium hydroxide .25 Sodium thiosulfa-te 20 Water to 1 liter.

gives a maximum density at least 5 times the maximum density obtained when the equally exposed silver halide emulsion is developed for 4 minutes at 20 C. in the following surface developer (I):

Grams p-Hydroxyphenylglycine 10 Sodium carbonate 100 Water to 1 liter.

and then without intermediate treatment, rendering developable the silver halide grains in the unexposed regions of said layer by immersing said layer in a developing solution free of antifoggant containing labile sulfur and free of silver halide solvent more powerful as a silver halide solvent than sulfite and containing a primary aromatic amino developing agent and an active methylene coupler compound capable of coupling with the oxidation product of said developing agent to produce a dye image, and developing to metallic silver said grains thus rendered developable.

DUDLEY B. GLASS.

FORREST A. RICHEY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,401,051 Crouse et a1 May 28, 1946 FOREIGN PATENTS Number Country Date 451,347 Great Britain Aug. 4, 1936 OTHER REFERENCES Wall: Photographic Emulsions, Publ. 1929 by Amer. Phot. Publ. 00., Boston, pages 52 and 53. 

1. THE METHOD OF OBTAINING A DIRECT POSITIVE DYE IMAGE IN A SILVER HALIDE EMULSION LAYER, WHICH COMPRISES EXPOSING TO LIGHT RAYS TO WHICH THE EMULSION IS SENSITIVE, A SILVER HALIDE EMULSION LAYER, A TEST PORTION OF WHICH UPON EXPOSURE TO A LIGHT INTENSITY SCALE FOR A FIXED TIME BETWEEN 1/100 AND 1 SECOND AND EVELOPMENT FOR 3 MINUTES AT 20*C. IN THE FOLLOWING ITERNAL TYPE DEVELOPER (II): 